Located in the southern Sacramento Valley, Jepson Prairie Reserve is an island of remnant natural prairie in a wide alluvial floodplain used primarily for agriculture. The reserve protects one of the best few remaining vernal-pool habitats, which are found only in the western United States and few other places in the world, as well as precious remnants of native bunchgrass prairie that once covered one-fourth of California.
As Olcott Lake and other large vernal pools evaporate each spring, millions of native wildflowers bloom around them, forming concentric rings of yellow, white, and blue. Many plant and animal species found on site are endemic to vernal-pool habitats, including three listed shrimp species. The site itself provides the only known home for the federally threatened delta green ground beetle and federally and state-endangered Solano grass. Altogether, over 400 species and 64 families of plants, including 15 rare and endangered plants, are found on site, notably dwarf downingia, federal proposed-threatened and state-endangered Colusa grass, and federal-candidates delta tule pea and fragrant fritillary.
Two sloughs flow across corners of the site, providing year-round habitat for a variety of wildlife, including beaver, otter, waterfowl, and several threatened fish species.
Reserve lands are owned by the Solano Land Trust (SLT) and protected by the trust and The Nature Conservancy (TNC); UC assists in the management of this site. The reserve is named in memory of pioneering botanist and Solano County native Willis Linn Jepson.
- Amphibian decline in California.
- Nesting biology of bees.
- Systematics of the genus Downingia.
- Spatial structure and plant-pollinator interactions.
- Effects of controlled burning of native bunchgrasses.
Fifty UC Davis-trained docents hold an annual open house and lead reserve tours from early March to mid-May; contact Solano County Festival of Flowers 707-421-1351. For docents, call Kate Mawdsley 530-758-5093
John Muir Institute of the Environment/NRS
Jepson Prairie Reserve website
Solano County, 12 mi south of Dixon on Highway 113; 45 minutes southwest of Sacramento; 1.5 hours northeast of San Francisco off Interstate 80; 25 minutes from Davis campus.
None; this site best suited for day use.
The reserve bibliography includes citations of journal articles, books, theses, art, and other works published about or based on activities conducted at the reserve.
floral and faunal lists in Jepson Prairie Handbook; GIS; meteorological.
Roving staff reserve manager; no on-site personnel.
634 hectares (1,566 acres)
2 to 8 m (5 to 25 ft.)
43 – 52 cm (17 – 20 in.) per year
January: 8 ºC (46 ºF)
July: 31 ºC (87 ºF)